Spatial distribution, sediment‒water partitioning, risk assessment and source apportionment of heavy metals in the Golmud River-Dabson Salt Lake ecosystem.

The occurrence of heavy metals is important for understanding their behavior in the sediments of river-salt lake ecosystems due to dramatically changes in salinity and flow velocity at the confluence area. Sediments and surface water samples were collected from the Golmud River-Dabson Salt Lake ecosystem, northwest China, to investigate the spatial distribution, sediment-water partitioning, risk assessment and source apportionment of heavy metals. Higher concentrations of heavy metals were observed in surface water from Dabson Salt Lake than in other regions. Additionally, a lower partition coefficient (K) for heavy metals was observed in Dabson Salt Lake, indicating their pronounced release from the sediments into the surface water. Elevated levels of heavy metals were detected at the confluence area between the Golmud River and southeast Dabson Salt Lake because of industrial activities. The assessment indices indicated that almost all heavy metals in the sediments of the Golmud River and Dabson Lake posed no pollution or low potential ecological risk. Notably, Pb in some samples from the Freshwater Zone reached heavy pollution levels. The results of APCS-MLR revealed that except Pb, other heavy metals were grouped into the first principal component, which originated primarily from rock parent materials. The second principal components (industrial source), explaining 46.97% of the variance, only included Pb. The natural, industrial and unidentified sources explained 76.56%, 14.95% and 8.49%, respectively, of the heavy metal sources. These findings can significantly contribute to the management of heavy metal pollution and enhance our understanding of heavy metal behavior in river-salt lake ecosystems.